Get 'Fetch' Hanging

I'm having trouble getting an agent checkout to complete successfully on v6.5.6.

The VCS root is configured successfully (i.e. Test connection works), but I'm getting the follwing in the log:

[21:27:34]: Checking for changes

[21:41:14]: Clearing temporary directory: C:\TeamCity\buildAgent\temp\buildTmp

[21:41:14]:Checkout directory: C:\TeamCityBuilds\Repo

[21:41:14]: Updating sources: agent side checkout...

[21:41:14]: [Updating sources: agent side checkout...] Will perform clean checkout. Reason: Checkout directory is empty or doesn't exist

[21:41:14]: [Updating sources: agent side checkout...] Cleaning C:\TeamCityBuilds\Repo

[21:41:14]: [Updating sources: agent side checkout...] VCS Root: Repo

[21:41:14]: [VCS Root: Repo] revision: 537701b12b2754aa63bf52606f36e4595615c028@1358eb931a0

[21:41:14]: [VCS Root: Repo] Cleaning C:\TeamCityBuilds\Repo

[21:41:14]: [VCS Root: Repo] The .git directory is missing in 'C:\TeamCityBuilds\Repo'. Running 'git init'...

[21:41:14]: [VCS Root: Repo] Fetching data for 'Repo'...

And the final step hangs.

Any idea what is causing this is or how I can figure out what is causing the hang?

Thanks.